Modified CAS9 compositions and methods of use

Abstract

The invention features Cas9 fusion polypeptides. In one embodiment of the invention, Cas9 is fused to a SNAP tag that enhances Cas9's gene repair function.

What is claimed is: 
     
       1. A Cas9 fusion polypeptide having the sequence of SEQ ID NO:2. 
     
     
       2. A polynucleotide encoding the polypeptide of  claim 1 . 
     
     
       3. An expression vector comprising the polynucleotide of  claim 2 . 
     
     
       4. A cell comprising the expression vector of  claim 3 . 
     
     
       5. A method for enhancing transgene integration efficiency, the method comprising expressing in a cell a vector encoding the polypeptide of  claim 1 , a small guide RNA, and a transgene suitable for integration into a genome. 
     
     
       6. The method of  claim 5 , wherein the integration efficiency is increased at least about 2-fold relative to the level present in a corresponding control cell expressing wild-type Cas9. 
     
     
       7. A method for enhancing Homologous DNA Recombination (HDR), the method comprising expressing in a cell vector encoding the polypeptide of  claim 1 , a small guide RNA, and a transgene suitable for integration into a genome.